TRL (technology readiness levels) method is widely used at present TRA (technology readiness assessment). This method relies too much on experts' knowledge and lacks objectivity. Meanwhile, since experts can only passively answer the questions set by TRL point by point during the assessment, experts' assessment thinking and orientation are unable to be effectively concentrated and specified, which result in redundant labor and low efficiency. This paper puts forward a TRA method based on multilevel reference condition (RC), sets up multilevel assessment parameter structure and introduces such key technologies as the determination of number of levels RC, establishment of RC, selection of RC characteristic parameter and expert assessment data processing. To a large extent, it solves the above-mentioned problems in the present TRA and gives an outlook to application of openness of assessing parameter structure.