Since the discovery of superconductivity in Bechgaard salts, quasi-one-dimensional (Q1D) organic materials have attracted intense interests in the past three decades. Due to their highly anisotropic structure and reduced dimensionality, a vast variety of phase transitions have been discovered in these compounds. In this talk, I will describe the magnetic properties of Q1D organic conductors. In the first part, I will show that orbital effect can lead to dimensionality change in the electron wave function and spectrum and thus give rise to rich angular magnetoresistance oscillations in Q1D conductors. In the second part, I will show that spin effect can stabilize charge density wave (CDW) phase in (Per)2Pt(mnt)2 at high magnetic fields and a unique field induced CDW phase can be realized.