Purpose – This study explores the relationship between IVs [Top Management Support (TOP) and Competitive Pressure (CP)], MV: Electronic Commerce Adoption (ECA) and DV: Business Performance (BP), which is the focus in the context among Small and Medium-sized Enterprises (SEMs) from Information Technology Sectors in Guangzhou city of China. Moreover, this study also explores the factors of each variables’ relationship by the collection of qualitative method based on the research framework that after it is tested followed by hypothesis question. Design/ methodology/ approach – 200 samples can be collected from Small and Medium-sized Enterprises (SEMs) in Guangzhou city of China by utilizing the convenience sampling method. And analyzing method in this study, the quantitative method can be selected by adopting IBMSPASS and PLS-SEM. Findings – Both Top Management Support (TOP) and Competitive Pressure (CP) have a significant positive impact on Business Performance (BP). Electronic Commerce Adoption (ECA) is an important factor to mediate the relationship between IVs [Top Management Support (TOP) and Competitive Pressure (CP)] and DV: Business Performance (BP). Research limitations/implications – The mediating role of Electronic Commerce Adoption (ECA) in the relationship between IVs (TOP, CP) and BP was studied using quantitative method for exploring and tested each variables’ relationship but not enough for exploring Key Successful Factors (KSFs) for implementing Electronic Commerce Adoption (ECA). The research background and research data are limited to Small Middle-sizes Enterprises (SMEs) and employees from Information Technology sectors in Guangzhou City of China. Originality/value – By studying the relationship and factors between IVs (TOP and CP), MV: ECA, and DV: BP, this paper will help to better understand how TOP and CP affect BP, and how ECA mediate the relationship between IVs: (TOP and CP) and DV: BP. With the increasing market competition and rising labor costs in China, improving and utilizing ECA for enterprises may be an important means to cope with future competition.