<p>This Part II serves as a companion pair for the Part I paper to provide further insights into the deformation behaviours of original and MICP-treated residual soil and sand, by using Acoustic Emission (AE). Special focus was placed on discerning the difference of mechanical behaviours between untreated and MICP-treated residual soils, by their changes of AE responses. A series of undrained triaxial tests same as those shown in Part I were simultaneously performed with the AE instrumentation. The developed AE measurement system was feasible for investigating the behavioural change relating to the soil fabric and correlating conventional mechanical measurements. In line with the finding from Part 1, the present AE analysis showed that the isotropic compression behaviour of MICP-treated residual soil was dominated by both elasticity and densification effect within soil pores. The MICP-treated residual soil tended to show more distinctive elastic behaviour by releasing less AE energy, as compared to the untreated counterpart because of the formation of elastic bonding and enhanced cementation that restricted the soil movement. This cementation effect was gradually diminished after the increase of consolidation stress due to the rearrangement of soil grains, partly associated with the mobility of adhered fines in soil bonding. The lightly treated residual soil manifested elasto-plastic shearing behaviour and preserved a greater extent of elasticity, as compared to the untreated residual soil. A distinctive elastic deformation behaviour was observed in the untreated and MICP-treated residual soils that subjected to over-consolidation effect. Upon the state of dilation and critical change of AE rate, the MICP-treated residual soil and sand possessed higher shear strength than the originally compacted soil.</p>