As the technology grow in wireless communication, the concept of multicarrier modulation come into picture. Orthogonal Frequency Division Multiplex(OFDM) prove itself invaluable for multicarrier modulation.OFDM subcarriers can overlap to make full use of the spectrum but at the peak of each subcarriers spectrum, the power in all the other subcarriers is zero. One of the major disadvantages of OFDM signal is large PAPR, which require power amplifier with large linear (gain) ranges. But to increase efficiency of power amplifier it gain become nonlinear and corresponding OFDM signal distort. So, a need for technique which reduces PAPR.Selective Mapping with phase rotation is one of the techniques to reduce PAPR .In this paper we have to compare the effect of different modulation (QPSK, DQPSK, and 4-QAM) on PAPR value of OFDM signal and its reduction by using selective mapping phase rotation method.