Pulse broadening caused by ultraviolet scattering communication may result in intersymbol interference(ISI)which can result in bit-error-rate(BER).It is studied the influence of pulse broadening on bit error rate of ultraviolet communication.Firstly,time domain distribution of received signal is calculated by ultraviolet transmission model.Secondly,probability density distributions of different combinations of code ‘1’ and code ‘0’ are convolved according to the rules of ‘11’,‘10’,‘01’and ‘00’ respectively,and then probability density distributions of ISI quantity caused by adjacent codes at both sides are obtained at sampling time.BER of the 4 cases caused by ISI is computed by an integral of ISI quantity probability density distributions within the bounds of ISI quantity at sampling time and critical value of ISI which causes BER.Simulation results show that the symbol rate should be lower than 1.36×108 Baud by LOS communication at a distance 5 km.By NLOS communication at distance 1 km,when elevations of transmitter and receiver are 20°,30° and 40° respectively,its corresponding symbol rates should be lower than 4.0×107 Baud,6.0×106 Baud and 3.6×105 Baud.As a result,BER caused by ISI can be ignored when ultraviolet is used for low speed wireless optical communication.