Mixed Quasi Newton simulation algorithm that is capable of calculating analog circuits containing mixed level of element models is presented. Conventional circuit simulators usually apply Newton method to solve nonlinear system equations resulted from circuit equations. At each Newton iteration step, it is necessary to reevaluate the Jacobian stamp of circuit elements. However, obtaining the Jacobian stamp of elements described by complex behavior models is a computationally expensive process. To reduce the number of Jacobian evaluations, we combine Newton method and Quasi-Newton method as a new updating scheme. The simulation results show that our algorithm can reduce the number of Jacobian evaluations and improve the simulation time, particularly when simulating circuits containing many behavior model elements.