Abstract: There are four questions for single-precision floating point trigonometric functions by CORDIC(Coordinate Rotation Digital Calculation)algorithm based on floating point adder, including the range of angles is not enough, large area, low operating frequency and high output delay. In this paper, a high computation circuit structure based on look up table and two-step iterative technology is proposed through converting floating-point operations into fixed-ponit operations and the optimization of scaling free CORDIC.It solves the problem that the CORDIC algorithm needs to use the multiplier and high numbers of iteration. This circuit is implemented on Altera's Stratix IV(EP4SGX70DF29C2X FPGA)and achieves Sin and Cosine in IEEE-754 standard.The synthesis results show the clock frequency can reach 282 MHz. Comparing to existed circuit structure, output delay and area reduced effectively, the calculation accuracy can reach 10E-7.