Abstract: This paper proposed an efficient algorithm NRSPF for calculating line spectrum pairs(LSP) parameters of speech signal. LSP parameters can be estimated by obtaining a root of high order nonlinear equation by Newton-Raphson function and Steffensen acceleration at first, then decreasing degrees with polynomial synthesis division, finally calculating other roots using Ferrari’s solution. Through analysis of practical example on TI-DSP, we found that NRSPF algorithm reduced the number of iterations, accelerated convergence rate and had small amount of calculation when compared with APF algorithm. In the case of precision increasing 10 times, 100 times and 1000times, APF algorithm maybe occurred division by-zero error and infinite loop while NRSPF algorithm not only avoided the error, but increased very few of iterations, got more accurate results, the convergence speed was still fast. The proposed algorithm has high performance, reliablity, strong real-time, which can be applied to low-bit rate real-time speech transmission system, speech encoding and decoding system, etc.