A driving module, being electrically connected to a control module and for driving a light emitting device with at least one light emitting element, is provided. The driving module has a driving circuit, which receives a control signal from the control module and transmits a drive current signal and a test current signal to the at least one light emitting element, so as to drive the least one light emitting element. A value of the drive current signal is expressed as If. A value of the test current signal is expressed as It. A relationship between the value of the drive current signal and the value of the test current signal satisfies the following equation (1), (It/If)=0.1%˜35% . . . (1), the driving circuit generates a feedback signal based on a status of the least one light emitting element. A light source system having the driving module is provided.