We synthesized a photo-crosslinkable polymide (polymide (PI)-chalcone-biphenyl (BP)) based polymer and control of pretilt angle for a nematic liquid crystal (NLC) using two kinds of the photodimerization methods by polarized UV exposure the photopolymer surfaces was studied. Pretilt angle of the NLCs using a conventional photodimerization method could be varied between 0$^{circ}$ and 3$^{circ}$, by controlling the condition of UV exposure. Pretilt angle of the NLCs using the conventional photodimerization method was higher than a in-situ photodimerization method.