The random number generator based on chaotic laser can generate a large number of true random numbers at high speed.However,raw random numbers cannot provide true randomness due to the additional technical noise introduced in the random number generation process.To achieve secure random number generation from information-theoretic standpoint,the randomness generated by entropy source must be quantitatively evaluated.In this paper,a chaotic laser-based random number generation device is experimentally constructed and the true randomness that can be extracted from raw random numbers is evaluated by conditional minimum entropy.Simultaneously,the effect of key parameters on the original randomness is discussed by replacing different devices.An information-theoretically falsifiable secure Toeplitz extractor is applied in the post-processing extraction process.Finally,the generation of secure random numbers is implemented.