The invention provides a process for preparing biocompatible directional carbon nanotube array reinforced composite hydrogel, which utilizes the chemical vapor deposition (CVD) technique, the radial cross linking technique and a freezing and thawing method. By permeating polymer sol into a carbon nanotube prefabricated body, aggregating and tangling problems during a compounding process of the carbon nanotube and polymer are resolved, boundary strength of a reinforcing phase and a basis phase is increased, and excellent performances of the nanotube on mechanics and electricity are played sufficiently. The composite hydrogel prepared by utilizing a physical cross linking process does not contain chemical additives and meets requirements on biocompatibility. The composite hydrogel prepared by the process has controllable length and direction of the reinforcing phase of a nanotube array, has integrated mechanics and electricity performances superior to those of the conventional hydrogel,and is adoptive to be applied to the biomedical field such as artificial articular cartilages, tissues engineering supports, nerve cell carries, biomimetic implanted electrode and the like.