PURPOSE: To provide the flow analyzing and estimating system of an injection mold for estimating the dimensions of a sprue in order to prevent burning an injection molding from developing.

CONSTITUTION: Characteristic value representing burning per parameter is calculated under the condition that the flow rate of resin is constant on the basis of the result of the analysis carried out at a filling analyzing section 11, in which the distributions of pressure, temperature and the like are calculated by carrying out the resin filling analysis respectively under the condition that the flow speed of resin, the diameter of a sprue, the length of the sprue are used as parameters. Further, the system concerned has a constitution equipped with a characteristic calculating section 12, in which the combination of parameters for realizing values per parameter obtained by modifying the occurrence limit of burning with safety factor, is obtained, and a display section 13, which graphically displays the relationship among the respective parameters for realizing the respective obtained combinations.