Lower-band chorus waves are known to play dual roles in radiation belt dynamics (electron acceleration and precipitation), and understanding their properties and excitation is very important. A systematic study of chorus waves properties in terms of background plasma parameters (electron perpendicular beta β_⊥ and the ratio of plasma frequency to electron cyclotron frequency f_pe /f_ce) has not been performed previously. We use burst mode data from Van Allen Probe A from 2014 to 2017 and develop an algorithm to extract individual lower band rising tone chorus elements. We statistically analyze four properties of rising tone chorus elements: time duration τ , frequency width ∆f , chirping rate Γ, and maximum intensity I_a. Statistical results show typical properties of chorus waves: I_a ∼ 0.09 nT, ∆f ∼0.08f_ce , Γ ∼2 × 10³ Hz/s, τ ∼ 0.015 − 0.25 s. On the nightside and dawnside, Γ shows wider spread and is more distributed over larger values, which is associated with the wider distribution of β_⊥. Chorus waves at duskside and dayside have larger values of τ , associated with smaller β_⊥ and larger f_pe /f_ce. The dependence of chorus wave properties on background plasma parameters is also examined. We show that normalized ∆f has positive correlation with β_⊥ and f_pe /f_ce. Normalized τ shows negative correlation with β_⊥ and positive correlation with f_pe /f_ce , respectively. Normalized Γ shows positive correlation with β_⊥ and negative correlation with f_pe /f_ce. These results help us better understand chorus waves excitation and their relation to the microburst.