This paper proposes a simple method for the estimation of symbol timing offset (STO) and fractional carrier frequency offset (FFO) in the cyclic prefix orthogonal frequency division multiplexing (CP-OFDM) based system. The purpose of this paper is to avoid effect of the inter symbol interference (ISI) by the multipath fading channel and inter carrier interference (ICI) by the performance difference of local oscillator between transmitter and receiver. To do this, the CP-based correlation function is proposed in the pre-FFT synchronization. Computer simulation is used to demonstrate the performance of the proposed method. The performance of the proposed method is compared with the conventional method and is evaluated by the time detection metric and mean square error (MSE).