In this paper,according to the principle of Newton iteration theory and the principle of Opposite Dividing Method for Intervals respectively,we calculate all the approximate root of the same function in the range of error allowed using Mathematica programming,by comparing the results of example,Newton derived the convergence rate faster and a smaller error than that of sub-interval method.

Using the interval marking method to quantify the rationality of bidding price,adopting the optimum floating reference price,these two methods are exercisable and suitable to the actuality of domestic construction market.