In this paper, a pulse temporal profile measurement scheme based on self-focusing lens coupling of single-mode optical fiber for small broadband frequency modulation pulse is introduced. Theoretical analysis and experimental results show that sampling energy with self-focusing lens coupling fiber decreases with the increase of the angle between lens and beam, but spectrum coupling efficiency of different orders is the same at the same angle. It means that the process of sampling will not introduce additional frequency modulation leading to amplitude modulation (FM-AM) effect. When the coupling efficiency drops in a half, the allowable drift angle of beam is 1 mrad. The technique scheme has advantages such as convenient to integrating, low cost and resistant to beam disturbance and electromagnetic interference. Besides, the sampling area has been expanded through the self-focusing lens that effectively improves the sampling energy and suppresses the adverse impact of beam cross section energy ups and downs on the measurement system. The technical scheme provides a certain theoretical and experimental basis for the improvement research of high power laser facility temporal profile measurement technology.