Abstract: A novel electrochemical sensor of crosslinked polyaniline (CPAN) was modified on Au electrode by cyclic voltammetric electropolymerization using aniline, p-phenylenediamine and 1,3,5-tris (phenylamino) benzene as the monomers. The electrochemical sensor obtained was characterized by AC impedence graph and electrochemistry. It was shown by the experimental results, that the structural unit of crosslinking agent 1,3,5-tris (phenylamino) benzene was successfully introduced into polyaniline chain. In comparison with linear PAN, the CPAN showed greater conductivity enhancement and faster electronic transmission speed. The CPAN modified Au electrode exhibited excellent electrocatalytic responses towards the oxidation of ascorbic acid. Under the optimized conditions, linear relationship between values of peak current and concentration of ascorbic acid was found in the range of 1.0×10-4-1.0×10-2mol·L-1 with detection limit (3S/N) of 3.3 ×10-5mol·L-1. Time of response of the sensor was found within 5 s. Values of RSD (n=6) found were in the range of 2.0%-2.5%. Recovery was tested by standard addition method, giving results in the range of 98.0%-102%.