The invention provides a fatigue strength measuring device and system. The device comprises a collecting unit, an excitation unit and a measuring unit; the excitation unit comprises a balance base, asupporting tool, an excitation device and a force guiding member, wherein the supporting tool and the excitation device are oppositely disposed on the balance base and fixedly connected to each otherby the force guiding member, a to-be-tested fastener mounted on the supporting tool is in contact with the force guiding member, and the excitation device applies an exciting force to the to-be-testedfastener via the force guiding member; the collecting unit is disposed on the to-be-tested fastener, and is configured to collect vibration response data of the to-be-tested fastener; the measuring unit is electrically connected to the collecting unit and the excitation device respectively, and is used for controlling the working state of the collecting unit and the excitation device and for calculating the fatigue strength of the to-be-tested fastener according to the collected vibration response data to obtain corresponding fatigue strength information. The device is high in measurement accuracy and measurement efficiency, and can reduce human resource consumption.