The construction and performance study is reported for a newly developed photoionization ion mobility spectrometer (UV-IMS) equipped with a 10.6 eV Kr lamp. The effect of the total voltage of drift tube, voltage and pulse width of ion gate on spectral resolution and sensitivity of UV-IMS were discussed. Their optimal values of pulse width, voltage of ion gate and drift tube are 0.15 ms, 80 V, and 2153 V respectively. The concentrations of benzene were prepared by means of exponential dilution method. The experiments show that the UV-IMS has a limit of detection at 400 ppt for benzene and its measurable linear dynamics range is over three orders of magnitude.