The present invention provides a method of terminal accessing credible PDA and accessing system. The accessing method is authenticating identity of the terminal before accessing credible PDA, comparing the present platform state of the credible PDA with the credible state value of the pre-stored terminal platform, if passing the comparison, the terminal and the credible PDA are linked. The access system includes a credible PDA, a terminal having credible platform module, an interface server of the credible PDA running, an interface client running on the terminal, a certificate server, an integrity reference server. The invention avoids the data damage caused by the safety problem of the terminal self, effectively prevents information being stolen, and also effectively prevents identity counterfeit, platform state counterfeit, greatly improves security of the data sharing.