Pulsed plasma thrusters (PPTs) are an attractive form of micro-thrusters due to advantages such as their compactness and lightweight design compared to other electric propulsion systems.Experimental investigations on their plasma properties are beneficial in clarifying the complex process of plasma evolution during the micro-second pulse discharge of a PPT.In this work,the multi-dimensional evolutions of the light intensity of the PPT plasma with wavelength,time,and position were identified.The plasma pressure was obtained using an iterative process with composition calculations.The results show that significant ion recombination occurred in the discharge channel since the line intensities of CⅡ,CⅢ,CⅣ,and FⅡ decreased and those of CⅠ and FⅠ increased as the plasma moved downstream.At the center of the discharge channel,the electron temperature and electron density were in the order of 10 000 K and 1017 cm 3,respectively.These had maximum values of 13 750 K and 2.3 × 1017 cm-3 and the maximum temperature occurred during the first half-cycle while the maximum number density was measured during the second half-cycle.The estimated plasma pressure was in the order of 105 Pa and exhibited a maximum value of 2.69 × 105 Pa.