A computer-implemented method for trusted login in a trusted login system comprising i) a first application system including a first server, ii) a second application system including a second server, and iii) a target client terminal, the method comprising: receiving (S2.1), at the second server and from the target client terminal, a request for trusted login, wherein the request for trusted login comprises a request to access a service page provided by the first server; generating (S2.2), by the second server, a trusted login token acquisition request, wherein the trusted login token acquisition request is based on the request for trusted login, the generating comprising i) obtaining a current trusted login identifier issued by the first server to the second server, wherein the first server issues the current trusted login identifier to certify the second server to obtain a temporary trusted login token, and ii) writing the current trusted login identifier into the request to access the service page provided by the first server to generate the trusted login token acquisition request; sending, from the second server, the trusted login token acquisition request to the first server; receiving (S2.3), at the second server, a temporary trusted login token from the first server, wherein the temporary trusted login token i) comprises service permission to log in to the first server and access the service page, ii) is generated by the first server based on the trusted login token acquisition request, and iii) is sent to the second server in response to the first server determining that the current trusted login identifier written into the request to access the service page by the second server is legal; and sending (S2.3), from the second server, the temporary trusted login token to the target client terminal, wherein the target client terminal sends the request to access the service page to the first server, wherein i) the request to access the service page includes the temporary trusted login token and ii) the first server permits the target client terminal trusted login to the first server in response to determining that the temporary trusted login token has service permission to access the service page and returns the service page to the target client terminal. receiving (S2.1), at the second server and from the target client terminal, a request for trusted login, wherein the request for trusted login comprises a request to access a service page provided by the first server; generating (S2.2), by the second server, a trusted login token acquisition request, wherein the trusted login token acquisition request is based on the request for trusted login, the generating comprising i) obtaining a current trusted login identifier issued by the first server to the second server, wherein the first server issues the current trusted login identifier to certify the second server to obtain a temporary trusted login token, and ii) writing the current trusted login identifier into the request to access the service page provided by the first server to generate the trusted login token acquisition request; i) obtaining a current trusted login identifier issued by the first server to the second server, wherein the first server issues the current trusted login identifier to certify the second server to obtain a temporary trusted login token, and ii) writing the current trusted login identifier into the request to access the service page provided by the first server to generate the trusted login token acquisition request; sending, from the second server, the trusted login token acquisition request to the first server; receiving (S2.3), at the second server, a temporary trusted login token from the first server, wherein the temporary trusted login token i) comprises service permission to log in to the first server and access the service page, ii) is generated by the first server based on the trusted login token acquisition request, and iii) is sent to the second server in response to the first server determining that the current trusted login identifier written into the request to access the service page by the second server is legal; and sending (S2.3), from the second server, the temporary trusted login token to the target client terminal, wherein the target client terminal sends the request to access the service page to the first server, wherein i) the request to access the service page includes the temporary trusted login token and ii) the first server permits the target client terminal trusted login to the first server in response to determining that the temporary trusted login token has service permission to access the service page and returns the service page to the target client terminal.