The limitation of low repetition rate for pulsed fiber laser makes data transmission rate lower, which has a serious impact on its application in the field of communications. In order to improve its performance and make it better applied to the field of communications, the pulsed fiber laser is modulated by three pulse position modulation (PPM) modulations and its impact on performance are studied experimentally. By changing the modulaton digits of three PPM modulations method, the influence of time slot width on modulation rate of pulsed fiber laser system is investigated, and the effect of the modulations on output power bit error rate is researched. The results show that the level pulse pastion modulation (L-PPM) modulation method is most suitable for pulsed fiber lasers and the modulation rate can be enhanced to 1.387 Mbit/s under the repetition rate of 200 kHz. The findings will be benefit for pulsed fiber laser applications in communications.