The interaction between laser and hohlraum can generate a large number of suprathermal electrons which obey the Maxwell distribution. The transport properties of the hot electrons and the suprathermal electrons in the hohlraum are investigated by using the Monte Carlo simulation program. In this paper we give the variations of hard X-ray spectrum with hot electrons and suprathermal electrons temperature and fraction, hohlraum size, and hohlraum thickness, and the determinant of efficiency of hard X-ray is obtained. The combination of Monte Carlo program and hot electrons induced by hard X-ray demonstrates the accuracy of the initial hot electrons.