Code tracking loop is a key component of Global Navigation Satellite System (GNSS) receivers which determines the accuracy of positioning performance. So analysis for its theoretical performance has been a research hotspot for decades. Many productive conclusions have been derived. However, most researches consider the impact of band limited channels in frequency domain, which is too computational to be applied in practical situations. To lighten the computational burden, an analytical expression of code tracking accuracy with correlation functions was derived, and the performance of code tracking loop could be easily assessed with the derived expression, which has guiding significance in the design of GNSS receivers.