The invention relates to a LED light source system with flexural and adjustable light spectrum, and the LED light source system belongs to the photobiology research instrument field. The invention mainly comprises system hardware, system software, and a light spectrum flexible combination and adjusting method. The LED is connected with a LED array substrate in a movable plug way, so as to form a unit module and to build a LED array; the LED array is connected with a LED constant current drive circuit, the circuit is connected with a controller through a data line and a supply line, and then is connected with a power supply. The light spectrum flexible combination and adjusting method comprises a wavelength combination, the light density adjusting, the photoperiod adjusting and control, and the operation frequency adjusting and control. The invention solves the problems that the traditional light source cannot provide multi optical spectrum parametric combination, and cannot exactly quantify and modulate the optical spectrum parameters, can perform flexural modulate to the optical spectrum parameters according to the demands of the photobiology research experiment, and can get series light source of the multi optical spectrum parametric combinations with different wavelengths, different light densities, different photoperiods and different operational frequencies through exact quantification.