To develop high-performance side-viewing all-fiber lenses applicable to the swept-source optical coherence tomography （SS-OCT） system， the factors influencing the performance of a type of side-viewing all-fiber lens and the sample production methods were studied. First， the graded-index （GRIN） optical model of the side-viewing full-fiber lens with the GRIN fiber was analyzed， and the graded parameters related to the performance of the side-viewing full-fiber lens were obtained. Second， the effect of the length of each component of the four-stage side-viewing lens “SMF+ NCF+ GRIN fiber + Angle prism” on its optical focusing performance was studied， and the appropriate length range of each component was designed. Finally， an ultrasmall side-viewing all-fiber lens with an outer diameter as small as 0.5 mm and a rigid length of 2.75 cm was fabricated. Experimental results show that the working distance （0.52 mm） and spot diameter （26.82 μm） of the lens are consistent with the theoretical analysis results. The lens sample is integrated into the SS-OCT imaging system to obtain clear tomographic images of biological tissues； thus， the performance of the designed lens is verified. The results indicate that the proposed method can be used to optimize the structural parameters of side-viewing all-fiber imaging lenses.