In the present study, a nanofluid filled cavity with sinusoidal temperature boundary condition, under the influence of an inclined magnetic field is investigated numerically. The LBM method is applied to simulate the Cu-Water nanofluid flow around an average temperature circular cylinder. In this study, the different braking manners of the magnetic field and the obstacle are compared for different field intensities and directions and various obstacle sizes and positions. The flow and heat transfer behavior of the nanofluid were observed for different Rayleigh numbers (103-106), Hartmann numbers (0-90), nanoparticles' volume fraction (0-6 %), magnetic field direction = (0-90o) and obstacle aspect ratios (0.05, 0.1 and 0.2) and positions (0-8). The results indicated that the influence of nanoparticles for this geometry and boundary condition is highly dependent on the Rayleigh and Hartmann numbers. Also, it was shown that for lower Ra numbers, the obstacle with an aspect ratio of 0.1 presents better heat transfer rate; while for higher Ra numbers the obstacle size is much less important than its position.