The electro-polymerization of L-Theanine was investigated for the first time on glassy carbon electrode and the polymeric conditions and mechanism were discussed in detail. Hereafter, a simple and sensitive electrochemical sensor based on the poly(L-Theanine) film was established for sophoridine sensing. The electrode process of sophoridine was then studied by cyclic voltammetry and its determination was achieved by amperometry. The results revealed that the poly(L-Theanine) membrane effectively decreased the oxidation potential of sophoridine and greatly increased its response current. And this sensor, fabricated easily and simply as well as very easy surface update, showed good response for sophoridine with a wide linear range from 1.0 x 10(-6) to 1.4 x 10(-4) mol L-1 and a low detection limit of 5 x 10(-7) mol L-1. The application of proposed method in analysis of real sample was also evaluated with good performance. This work promoted the potential applications of amino acid materials in electrochemical sensors. (C) 2013 Elsevier B.V. All rights reserved.