Subject, object type NLO polyimide in addition to guest molecules escape and readily decompose at high temperatures outside, poor compatibility with the host polymer and guest molecules has become one of the problems of this material. Poor compatibility, limiting the doping content NLO chromophore molecules, generally less than 10%. You need to increase the molecular orientation of the polarization electric field is applied to a very high, easily lead to the breakdown of the insulating polymer film. High NLO chromophore content, prone to phase separation during film formation. Also chromogenic molecule crystallization also reduces the transparency of the polymer film. In order to overcome the above drawbacks can be NLO chromophore molecules covalently bonded to the polymer chain, in order to obtain greater nonlinear optical coefficient and a higher thermal stability. NLO chromophore molecules of this system as a side chain connected to the polymer chain, it can achieve a high concentration of non-linear optical group grafted chromophore molecules gathered crystallization does not occur, phase separation and a concentration gradient in the polymer . Key chromophore pick hindered motion of the polymer chain. In most cases, TG containing the same concentration of chromophore chain type polymer system was significantly higher than the subject-object-based systems, thereby slowing the polarization orientation relaxation of chromophore molecules. How NLO chromophore key high nonlinear optical characteristics of the study is the key to receiving system on high TG of the polymer backbone.