diff --git a/libchinese-segmentation/chinese-segmentation.cpp b/libchinese-segmentation/chinese-segmentation.cpp
index 1492ee1..e3a1207 100644
--- a/libchinese-segmentation/chinese-segmentation.cpp
+++ b/libchinese-segmentation/chinese-segmentation.cpp
@@ -55,14 +55,16 @@ ChineseSegmentation *ChineseSegmentation::getInstance()
     return global_instance_chinese_segmentation;
 }
 
-QVector<SKeyWord> ChineseSegmentation::callSegement(QString& str)
+QVector<SKeyWord> ChineseSegmentation::callSegement(QString str)
 {
     std::string s;
     s=str.toStdString();
+    str.squeeze();
 
     const size_t topk = -1;
     std::vector<cppjieba::KeywordExtractor::Word> keywordres;
     ChineseSegmentation::m_jieba->extractor.Extract(s, keywordres, topk);
+    std::string().swap(s);
     QVector<SKeyWord> vecNeeds;
     convert(keywordres, vecNeeds);
 
diff --git a/libchinese-segmentation/chinese-segmentation.h b/libchinese-segmentation/chinese-segmentation.h
index 1ea1ecf..db054c4 100644
--- a/libchinese-segmentation/chinese-segmentation.h
+++ b/libchinese-segmentation/chinese-segmentation.h
@@ -48,7 +48,7 @@ class CHINESESEGMENTATION_EXPORT ChineseSegmentation
 public:
     static ChineseSegmentation *getInstance();
     ~ChineseSegmentation();
-    QVector<SKeyWord> callSegement(QString &str);
+    QVector<SKeyWord> callSegement(QString str);
     void convert(std::vector<cppjieba::KeywordExtractor::Word>& keywordres,QVector<SKeyWord>& kw);
 private:
     static QMutex m_mutex;
diff --git a/libsearch/file-utils.cpp b/libsearch/file-utils.cpp
index 7912066..0cb80c7 100644
--- a/libsearch/file-utils.cpp
+++ b/libsearch/file-utils.cpp
@@ -529,6 +529,11 @@ void FileUtils::getDocxTextContent(QString &path,QString &textcontent)
             {
                 QDomElement wt = wr.firstChildElement("w:t");
                 textcontent.append(wt.text().replace("\n",""));
+                if(textcontent.length() >= 682666) //20480000/3
+                {
+                    file.close();
+                    return;
+                }
                 wr = wr.nextSiblingElement();
             }
             wp = wp.nextSiblingElement();
@@ -545,7 +550,7 @@ void FileUtils::getTxtContent(QString &path, QString &textcontent)
     if(!file.open(QIODevice::ReadOnly|QIODevice::Text))
         return;
 
-    QByteArray encodedString = file.readAll();
+    QByteArray encodedString = file.read(20480000);
 
     uchardet_t chardet = uchardet_new();
     if(uchardet_handle_data(chardet,encodedString.constData(),encodedString.size()) !=0)
diff --git a/libsearch/index/construct-document.cpp b/libsearch/index/construct-document.cpp
index 2021fc2..3b9b780 100644
--- a/libsearch/index/construct-document.cpp
+++ b/libsearch/index/construct-document.cpp
@@ -118,7 +118,7 @@ void ConstructDocumentForContent::run()
     QString uniqueterm = QString::fromStdString(FileUtils::makeDocUterm(m_path));
     QString upTerm = QString::fromStdString(FileUtils::makeDocUterm(m_path.section("/",0,-2,QString::SectionIncludeLeadingSep)));
 
-    QVector<SKeyWord> term = ChineseSegmentation::getInstance()->callSegement(content);
+    QVector<SKeyWord> term = ChineseSegmentation::getInstance()->callSegement(content.left(20480000));
 
     Document doc;
     doc.setData(content);
@@ -135,6 +135,7 @@ void ConstructDocumentForContent::run()
     _doc_list_content->append(doc);
     _mutex_doc_list_content.unlock();
     content.clear();
+    content.squeeze();
     term.clear();
     return;
 }
diff --git a/libsearch/parser/binary-parser.cpp b/libsearch/parser/binary-parser.cpp
index b16deb4..2057ed4 100644
--- a/libsearch/parser/binary-parser.cpp
+++ b/libsearch/parser/binary-parser.cpp
@@ -5061,6 +5061,8 @@ bool KBinaryParser::read8DocText(FILE *pFile, const ppsInfoType *pPPS,
 					ushort* usAucData = (ushort*)ptaucBytes;
                     content.append(QString::fromUtf16(usAucData).replace("\r",""));
                     usAucData = (ushort*)xfree((void*)usAucData);
+                    if(content.length() >= 682666) //20480000/3
+                        break;
 				}
 				else
 				{