We present the measurements of J/ψ production at mid-rapidity via the di-muon decay channel in p+p and p+Au collisions at √ s NN = 200 GeV by the STAR experiment at RHIC. In p+p collisions, the measured inclusive J/ψ cross section can be qualitatively described by model calculations. The J/ψ polarization parameters, λ θ , λ φ as well as the frame-invariant quantity λ inv , are presented as a function of transverse momentum in both the helicity and Collins-Soper frames. No significant polarization is observed. In addition, the nuclear modification factor for inclusive J/ψ in p+Au collisions is similar to that measured in d+Au collisions and favors an additional nuclear absorption effect on top of the nuclear PDF effect.