A distributed eavesdropping method for directional modulation is proposed. Firstly, the possibility of distributed eavesdropping is analyzed，and it is pointed out that the eavesdroppers can use sufficient illegal channels to imitate the legitimate channel and eliminate the interference. Then, the constant modulus property of Phase-Shift-Keying(PSK) modulation is applied to design a distributed receive approach and a theft weighted algorithm. Simulation results show the eavesdropping method could get confidential message，pointing out that directional modulation technology still remains unsafe in theory.