As a single carrier modulation scheme，Discrete Fourier Transform Spread Orthogonal Frequency Division Multiplexing(DFT-S-OFDM) has lower Peak to Average Power Ratio(PAPR) than the conventional OFDM. And it has been adopted as the uplink modulation scheme in 3GPP’s Long Term Evolution(LTE). In this paper, an improved local Maximum Likelihood(ML) based method is proposed for DFT-S-OFDM detection. The two most probable symbol positions are selected after 1st order Minimum Mean Square Error-Maximum Likelihood(MMSE-ML) detection, and the ML detection is performed on these positions. Numerical simulations show that the proposed method has little performance loss and huge computation reduction compared to the 2nd order MMSE-ML. And the proposed method has a 0.5 dB-0.7 dB gain compared to the 1st order MMSE-ML with little additional computations.