A new nonlinear optical crystal^ disodium sulfosaiicylaLe (DSB) is reported. Large single crystal with good optical quality have been grown in soluiion by the cooling method. X-ray structural determination shows that the crystal belongs to orthorhombio system with poini group mm 2. Its transmitted spectrum is in the range of 870~ 1300 nm. The refractive indices ai various wavelengths as well as the effeoiive nonlinear coefficients dm have been measured. Based on the oalculafcion of the phase-ma tching angles φι and φπ, the values of t/3i and. d32 of DSS crystal relative to of KDP crystal have been obtained. It is found, thai the SHG conversion efficiency of DSS crystal is about 3.5 times than ihai of KDP crystal. Moreover, the optical damage threshold is higher than 200 MW/om2. The crystal exhibits a somewhat better deliquescent resistant proper ty than the KDP crystal. is believed thai this crystal has some practical values of using as the SHG element for 1.06 μ laser.