A2Mo3As3 (A = alkali metal) is a brand-new novel family of molybdenum arsenide based quasi-one-dimensional (Q1D) superconductors with a transition temperature between 10.4 to 11.5 K, discovered just a couple of months ago. The crystal structure of these materials contains special Q1D (Mo3As3)2– linear chains separated by columns of alkali metal cations. Since Mo and Cr belong to the same group of transition metals with similar electronic configuration, A2Mo3As3 superconductors, like their sister families A2Cr3As3 and A1Cr3As3, expected to show exotic superconducting properties. We propose to study the magnetic properties of K2Mo3As3 using zero-field and longitudinal-field µSR measurements and superconducting properties, especially the superconducting pairing mechanism from gap symmetry using transverse-field µSR measurements. We ask for 4 days of MuSR beamtime for the proposed study.