A scheme for measurement and control system on grain situation is presented in this paper. This system is mainly composed of sensor network, measurement and control extension, communication host and host computer. Measurement and control extension centres on microcontroller C8051 to accomplish the measurement of grain temperature and humidity in granary. Instruction is transferred to measurement and control extension by communication host, at the same time, transferring the data measured by extension to host computer. Host computer achieves the regimentation of whole system by applying PC. Compared with traditional ones, this measurement system is much more simple, low-cost, efficient and responsive, with profoundly immediate significance and wide prospect.