Altered lipid metabolism is increasingly recognized as a signature of cancer cells. Enabled by label-free spectroscopic imaging, we performed quantitative analysis of lipogenesis at single-cell level in human clear cell renal cell carcinoma (ccRCC), which accounts for about 90% kidney cancers. Our hyperspectral stimulated Raman scattering (SRS) imaging data revealed an aberrant accumulation of lipid droplets in human clear cell renal cell carcinoma (ccRCC), but no detectable lipid droplets in normal or benign kidney tissues. We also found that such lipid accumulation was significantly higher in low grade (Furhman Grade≤2) ccRCC compared that in high grade (Furhman Grade≥3) ccRCC, and was correlated well with the prognosis of ccRCC. Moreover, cholesteryl ester is the dominant form of lipids accumulated in ccRCC. Besides, the unsaturation level of lipids was significantly higher in high grade ccRCC compared to low grade ccRCC. Furthermore, depletion of cholesteryl ester storage significantly reduced cancer proliferation, impaired cancer invasion capability, and suppressed tumor growth and metastasis in mouse xenograft and orthotopic models, with negligible toxicity. These findings herald the potential of using lipid accumulation as a marker for diagnosis of human ccRCC and open a new way of treating aggressive human ccRCC by targeting the altered lipid metabolism.