Incorporating microcomputer into instruments will no doubt simplify their structures, expand functions and improve presision, As far as instruments are concerned, being intelligent implies automatic sampling, data processing, automatic checking, automatic verification and various compensated correcting. Modularized structure, which is embodied in the design of intelligent instruments, consists mainly of hardware module and software module. The paper deals with the intelligents instruments including their working principles and modularized structures(both hardware and software). The principle and structure of multichannel multifunctional integrator are also described.