Abstract: In order to solve the problem of low intelligent and difficult measurement and control of greenhouse group, a coordinated control method of terminal variables of multi greenhouse IoT group control is proposed based on Improved PSO algorithm. Through the construction of multi greenhouse hierarchical distributed Internet of Things group control integrated system based on big data, effectively integrates big data technology, Internet of Things technology, sensor technology and intelligent control technology, adopts multi parameter and multi variable coordinated control method of single greenhouse to realize intelligent coordinated control of single greenhouse, by adding a general controller, according to the recorded multi greenhouse crop growth environment parameters. When the improvement value of the optimization result is less than 1%, the optimization will stop and the optimal parameters will be output at this time to complete the coordinated control of multi greenhouse group control terminal variables. The experimental results show that the average value of the target temperature is 25.6 ℃, the error value is 1.4 ℃, the average relative humidity is 47.60%RH, and the error value is 2.4%RH. The light intensity and carbon dioxide concentration can basically maintain a small range of fluctuation, and the environmental parameters can be adjusted to the preset target environmental parameters of greenhouse in a short time, so as to improve the multi temperature Intelligent control degree of terminal variables in group control of room Internet of Things.