Photoacoustic microscopy (PAM) is a high-resolution imaging modality of photoacoustic imaging. Laser light interacts differently with the tissue based on its wavelength. Typically, in PAM systems, multiple wavelengths are employed to extract functional and molecular information from the tissue by targeting different absorbers like oxyhemoglobin, deoxyhemoglobin, lipids, melanin, water etc. This is done either by using multiple lasers of different wavelengths or more recently with one laser that produces different wavelengths through stimulated Raman scattering (SRS) phenomena induced in polarization maintaining single mode fibers (PM-SMF). However existing multispectral PAM (MS-PAM) systems are slow. This is because these systems utilize mechanical scanning where transducer is held on x-y stage and mechanical moved from one point to the other. Here, we describe the development of a laser scanning multispectral PAM (LS-MS-PAM), where a unique spiral optical scanning is employed, and transducer is placed in a fixed position. This makes the multispectral PAM system faster along with functional and molecular imaging capability. With the developed system, oxygen saturation, hemoglobin concentration, blood flow and vascular diameter measurement can be acquired with a frame rate of less than 1 second. Phantom study and animal study were performed to validate fast multispectral imaging characteristics of our developed system.