A new Nickel(Ⅱ) complex was sythesized with 2-hydroxy-4-methoxybenzophenone and NiCl2 used as raw materials, and characterized through IR, TG, UV. The results show that the complex ratio of 2-hydroxy-4-methoxybenzophenone to Nickel(Ⅱ) is 1∶2; the metal ion coordinates with oxygen atoms of -C=O and next to -OH group. Meanwhile, its thermal decomposition process is divided into three weightless stages during 120～630 ℃, of which 120～258 ℃ is the process of a coordinated water lost, and 258～630 ℃ has two thermal decomposition stages. Finally, the complex is decomposed into NiO. UV analysis indicates that thermal stability of the complex is better than that of 2-hydroxy-4-methoxybenzophenone. The complex remains the quality of absorbing ultraviolet radiation.