At present, most of the research work of ancient pottery protection is related to the selection and evaluation of consolidation materials. Research on the protection mechanism, especially in the field of salt weathering, is very limited. In this paper, TEOS, Paraloid B72 and WD10 were selected to be used for consolidation and mitigation of salt efflorescence on the simulated ancient Qin terracotta samples. The morphologies of salt crystals on surface of untreated and treated terracotta samples were investigated; the related salt crystallization mechanism is discussed in a preliminary way. Water absorption, color change, compressive strength and salt artificial ageing tests were conducted on the simulated terracotta samples after treatment with these materials. The results show that the terracotta samples treated with TEOS gain better compressive strength, but that TEOS had no positive effect on mitigating salt efflorescence; WD10 greatly reduced water absorption and is able to mitigate salt crystallization damage; Paraloid B72 deepened the treated terracotta sample color and enhanced salt efflorescence. It show that surface modifications produce different types of salt efflorescence, which relates to the hydrophobicity and permeability generated from protective material. The harmful effect of Paraloid B72 is also captured attention.