Frequency-sweeping　lasers　have　drawn　considerable　attentions,　especially　in　FMCW　LIDAR.　The　frequency　sweeping　single-frequency　PM　fiber　laser　is　respectively　realized　by　piezoelectric　(PZT)　modulation　and　pump　modulation,　which　using　the　same　Er-doped　distributed　Bragg　reflection　(DBR)　fiber　cavity.　The　central　wavelength　is　1552.49　nm　with　the　extinction　ratio　of　above　20　dB.　The　frequency　sweeping　range　of　PZT　modulation　is　seen　to　be　up　to　745　MHz　under　the　modulation　repetition　rate　of　1Hz,　and　the　modulation　repetition　rate　of　the　pump　can　be　tuned　from　1Hz　to　20　kHz.　However,　the　frequency　sweeping　range　and　tunable　range　of　pump　modulation　is　635　MHz　and　from　1Hz　to　10　kHz,　respectively.　Comparing　with　both　methods,　the　PZT　modulation　has　wider　sweeping　range　and　tunable　range,　however,　the　mechanical　resonance　will　be　occurred.　The　pump　modulation　indicates　virtually　linearly　frequency　modulation.　Future　works　to　achieve　more　characteristic　of　two　modulation　methods　are　undergoing.