Relevance. Increasing the depth of heavy hydrocarbon raw materials refining is aimed at petroleum products recovery with the low content of resinous asphaltene and heteroatomic organic compounds, as well as incremental light fractions providing. One of the promising directions of advanced processing of heavy crude oils and oil residues are processes using amorphous aluminosilicates and zeolites. Of particular interest is the study of their catalytic activity during cracking aimed at thermal transformations of high-molecular components. Aim. Study of the amorphous aluminosilicate modification effect on the composition of cracking products of heavy Ashalcha crude oil. Object. Heavy crude oil from the Ashalchinskoe field (Republic of Tatarstan, Russia). Methods. Gas chromatography-Mass spectrometry (GC/MS) analysis, liquid adsorption chromatography. Results. Laboratory cracking of heavy Ashalcha crude oil in the presence of amorphous aluminosilicate (Al-Si) and its modified form (NiCrWC/Al-Si) was carried out in a batch reactor. The authors have studied the amorphous aluminosilicate modification effect on the composition of cracking products and directional changes of oil constituent thermal transformations. It was shown that NiCrWC modifier amplifies the cracking effects of amorphous aluminosilicate, as evidenced by the decrease of resins and asphaltenes content in liquid products compared to their content in products of cracking with Al-Si. The destruction of resins and asphaltenes during cracking with NiCrWC/Al-Si provides incrementation of oils yield by 10,2 wt % compared to the initial crude oil. According to the group hydrocarbon composition of oils, it was established that the carrying out of crude oil cracking in the presence of catalytic additives Al-Si и NiCrWC/Al-Si occurs the incrementation of saturated and aromatic hydrocarbons content. GC/MS analysis of individual hydrocarbon composition showed that the isoprenoids/n-alkanes ratio in the products of cracking with Al-Si and NiCrWC/Al-Si is 0.7 and 0.3, respectively, versus 2.9 in initial crude oil. Cracking in the presence of Al-Si and NiCrWC/Al-Si degrades C₁₃–C₂₃ trimethylalkyl-substituted benzenes to form C₈–C₁₁ methyl- and alkyl-substituted benzenes. Moreover, their content is higher in products of cracking with NiCrWC/Al-Si additive than in the Al-Si catalyzate. It was established that the most essential quantitative and qualitative changes in the hydrocarbon composition occur during cracking in the presence of NiCrWC/Al-Si catalytic system.