The invention discloses a one-man operation dangerous condition detecting method and a one-man operation automatic alarm method. The one-man operation dangerous condition detecting method includes the following steps: P1, starting a handheld terminal one-man operation mode; P2, adopting a gravity sensor for real time detection of the status of a handheld terminal; P3, determining that a user is in a dangerous condition when detecting that the handheld terminal is in a static state for a period of time which is longer than a predetermined time period. The one-man operation automatic alarm method includes the following steps of S1, early warning: vibrating in an uninterrupted manner after determining that the user is in the dangerous condition; S2, local alarm: sending buzzing sound by the handheld terminal for sending rescue signals to the surrounding after judging that the user is in an emergency condition if the user does not take any action or move after the early warning; S3, remote alarm: sending remote alarm if the user does not respond to the local alarm.