In order to mitigate the network performance reduction by congestion problem, a new Passive Queue Management (PQM) algorithm named Drop Front n based on Cloud Model (DFCM) was proposed with drop front. At first, the drop packet strategy and drop packet probability were presented by considering network queue length and arrival rate in this algorithm, and the actual queue length was computed with cloud model. Finally, a simulation with NS2 and Matlab was conducted to study the key influencing factors of this algorithm. The results show that, compared with Drop Tail and DFSQ (Drop Front n based on Synchronized Queue) algorithms, DFCM has better suitability in instantaneous queue length variance and effective packet transmission.