For the Boltzmann-Bose equation, a coercivity estimate for the linearized operator around a Bose-Einstein distribution is obtained to reveal the singularity when the temperature of the distribution is close to the critical condensation temperature. Based on the well-established coercivity estimate for the classical Boltzmann equation without angular cut-off, the proof relies on the projections on two different null spaces of the linearized operators in the hard potential case. For the soft potential, an induction argument is applied to reduce the kinetic factor in the cross-section to some suitable weight functions by using the gain of moment due to the angular singularity. The talk is based on a joint work with Yulong Zhou.