Objective:To study the regularity of syndrome-treatment and prescription-drugs of proteinuria in chronic nephritis in contemporary Chinese medicine using data mining technology. MethodsLiteratures published in recent 20 years about proteinuria in chronic nephritis in contemporary Chinese medicine were retrieved and screened in the database of China National Knowledge Infrastructure (www.CNKI.net) and Wanfang Medical Network (http://med.wanfangdata.com.cn/), and the information on syndrome-treatment and prescription-drugs was extracted to establish a database. In statistical software, frequency statistics, association rules analysis, cluster analysis and other methods were used for data mining to explore the relevant regularity.  Results:①The traditional Chinese medicine (TCM) syndromes from high to low frequency were spleen and kidney deficiency, qi and yin deficiency, external attack of wind pathogen, liver and kidney yin deficiency, excessive dampness and heat, etc. ②In terms of the function of prescriptions, tonifying recipes showed the highest frequency of occurrence, 252 times; followed by dampness dispelling recipes, 128 times; and stasis removing recipes, 51 times. ③In terms of the frequency of prescription application, the top five prescriptions are Shenling Baizhu Powder (30 times), Liuwei Dihuang Pill (29 times), Shenqi Dihuang Decoction (20 times), Erzhi Pill (18 times) and Jinkui Shenqi Pill (18 times). ④Astragalus root is the most frequently used traditional Chinese medicine. ⑤After cluster analysis of data on traditional Chinese medicine, five new drug combinations were found, including “poria, rehmannia root, cornus fruit, dioscorea root, alisma tuber, tree peony bark, astragalus root and ovate atractylodes root”, “codonopsis root, dodder seed, aged tangerine peel, licorice root, cherokee rose fruit and euryale seed” and “salvia root, motherwort, Chinese angelica, Sichuan lovage root, red peony root, peach kernel and safflower”. ⑥The core Chinese medicines for proteinuria in chronic nephritis were mainly qi-tonifying and spleen-invigorating drugs (astragalus root, ovate atractylodes root and poria) and drugs supplementing the kidney and astringing essence (cornus fruit, dioscorea root, rehmannia root and euryale seed).  Conclusion:①According to TCM, the basic pathogenesis of proteinuria in chronic nephritis is spleen and kidney deficiency. Wind pathogen, dampness-heat and blood stasis are the common pathological factors. Clinically, syndrome differentiation and treatment can be carried out considering six syndromes:spleen and kidney deficiency, qi and yin deficiency, liver and kidney yin deficiency, external attack of wind pathogen, excessive dampness and heat and blood stasis. ②Shenling Baizhu Powder, Liuwei Dihuang Pill and Shenqi Dihuang Decoction are the commonly used prescriptions clinically; the core Chinese medicines for proteinuria in chronic nephritis are mainly qi-tonifying and spleen-invigorating drugs (astragalus root, ovate atractylodes root and poria) and drugs supplementing the kidney and astringing essence (cornus fruit, dioscorea root, rehmannia root and euryale seed).