V2V communication is part of VANET technology with physical layers using OFDM according to IEEE S02.11p standards. One of the factors affecting the performance of vehicle-to-vehicle communication is the doppler frequency. Doppler arises because of changes in the speed of the vehicle and affected by the surrounding object, thus decreased performance of BER and channel capacity. This study simulates a vehicle-to-vehicle communication system using adaptive modulation and analyzes the performance of BER and calculates system capacity. The adaptive modulation parameter based on the signal gain channel which is affected by doppler. Adaptive modulation uses three types of non-adaptive modulation ie BPSK, QPSK, and 16-QAM. the use of non-adaptive modulation is determined based on two thresholds on the gain channel. This study uses three thresholds of adaptive threshold This study uses three variations of adaptive threshold. The results of this adaptive modulation provide better performance than BPSK non-adaptive modulation, such as lower SNR needed to achieve desired BER and increment in channel capacity. The threshold adaptive 1 (0.25 and 0.5) has the best performance. To achieve BER 10-3, the SNR needed is 6 dB lower compared to BPSK and the channel capacity increases up to 120% at the highest normalized doppler (0.01).