A computer-implemented method and system for reconstructing a response message to an improper accessing request in a web application environment. The method includes: obtaining the URL of a web application to be accessed by the improper accessing request and the error parameter information of the improper accessing request; obtaining a response template based on the obtained URL of the web application to be accessed; and merging the obtained error parameter information of the improper accessing request with the obtained response template to generate a reconstructed response message for the improper accessing request. The system includes: a message obtaining device; a response message template obtaining device; and a response message merging device.