The paper concerns the improvement of two primary technologies for 3ω(351nm) shot experiment in SG-Ⅱ facility target area ,which are 3ω target alignment laser and optical viewing system .The 1ω (1 053nm) laser is exported form the Nd:YLF laser and passes the KTP+BBO system to acquire the 3ω laser.And the 3ω laser is coupling-out with main laser.In order to improve the laser accurately position on the target,the reflection optical system is replaced by the transmission optical system,which avoids the effect of chromatic aberration.