A PDA-based diagnosis and identification system for fruit tree diseases and insect pests, including a remote PC system and a mobile client system, the remote PC system includes a PC database, a PC index library, a data acquisition module, an index management module, a rule engine and a transmission module, and the data acquisition module will The collected original information is uploaded to the PC database; the index management module scans the data in the PC database one by one, and generates corresponding index entries according to the rules in the rule engine, and saves them in the PC index library; both the PC database and the PC index library are transmitted The module communicates with the mobile client system. The present invention is a portable and fast diagnosis and recognition system for pests and diseases, which realizes the diagnosis of diseases, insects, weeds and weeds in the field and comprehensive control technology guidance; it can complete data collection, index management, feedback analysis and PDA (mobile phone) retrieval, and integrates mobile phone communication, diagnosis and recognition of diseases and insect pests Function in one, improve work efficiency.