A chromatic aberration metalens with ideal focal length of 250μmat the mid infrared band 3.6～3.8μmis designed based on artificial neural networks method.Sample of 20 frequency points at the working band are collected,and an average focal length of 227.58μmand an average focusing efficiency of 8.19% are obtained.The substrate of the meta unit is silicon dioxide,and the dielectric unit is a combination of two nano silicon bricks.The phase control of the meta unit is achieved based on resonance phase and geometric phase.The trained artificial neural network can use any structural parameters of the meta unit to predict the corresponding phase response.The training loss of the network model is 2.54×10 -5,and the prediction time of the real and imaginary parts of the phase response is less than 0.2 seconds under this model.This work provides a novel design approach fora new idea for the research and development of achromatic meta lenses.