1. A computer-based growing simulation method for a role playing game implemented on a computer having a read and write recording medium for storing data executable by the computer, an output unit linked to the computer and an input unit linked to the computer to complete the game by executing the following steps: a. providing a role library which includes: data of a plurality of different roles that are presentable in visual picture images on the output unit; and basic parameter groups corresponding to every role, the parameter groups. including at least one parameter, and an age parameter for every role in the game; b. providing an event library which includes: data of a plurality of different simulated environments including simulated lifelike environment objects and things which are presentable in visual picture images on the output unit; and selection item groups for any one of the roles to show behaviors accordingly including at least one selection item, any selection item being related to a selected event in the event library, wherein triggering (selecting) a selection item will cause the computer to change the role's basic parameter value in the corresponding event; c. providing a relation recording table for recording the relationship between every role and the events; d. displaying in a visualized fashion the role and the role's behaviors corresponding to the events on the output unit; e. receiving signals or commands of devices operated by players through the input unit for changing the role's behaviors or triggering a selected preceding event; and f. processing the corresponding events through the processing unit and sending processing results in visualized formats to the output unit.