In order to solve the optimal deployment of agricultural multi-robot communication nodes in the cooperative operation between rows in the traditional apple orchard, the propagation characteristics of 2.4GHz Wi-Fi signal in the traditional apple orchard (mature stage) were studied. The signal transmitting and receiving nodes were vertically deployed at the heights of 0.45m, 0.55m, 0.65m and 0.75m from the ground, respectively. The nodes were horizontally deployed according to the four typical formation modes of multi-robot linear, small spacing V-shaped, large spacing V-shaped and parallel. The receiving intensities of communication signals at different heights and at different distances under the above four formation modes were measured. The research results showed that among the above four formation modes, the signal attenuation in the linear formation mode was the slowest. Therefore, the best way of multi-robot formation in the traditional apple orchard was linear, and the node height was best deployed at about 0.2m down the first branch of the fruit tree. The regression analysis of path loss data showed that it conformed to the logarithmic path loss model under the height of each wireless communication signal node and the typical formation mode of each multi-robot, and the R2 of the model was between 0.860 and 0.989. At the same time, a path loss model for predicting 2.4GHz Wi-Fi signal in traditional apple orchard was established. At the same time, other apple orchards were selected to verify the accuracy of the prediction model, R2 was 0.947~0.967, RMSE was 1.489~2.432dBm. The model can better predict the path loss of Wi-Fi signal in traditional apple orchard, and the research result can provide reference for the deployment of communication nodes of agricultural multi-robot in traditional apple orchard.