BESIII collected the world largest data samples of 2.93, 0.482 and 0.567 fb−1 data at 3.773, 4.009 and 4.6 GeV, respectively. Based on these data samples, BESIII perform some analy- ses of D0(+), D+s and Λ+c , which are important to understand the weak decay machanism of charmed mesons and baryons. The leptonic decays of D+ → τ+ντ and D+s → l+νl are measured. The dynamics of D+ → K ̄0e+νe, π0e+νe and K−π+e+νe are studied, and the parameters of the form factors and CKM matrix elements |Vcs(d)| are extracted. In addition, the branching frac- tions for D+ → K ̄0μ+νμ, K ̄0e+νe, D+s → η(′)e+νe are also provided. The amplitude analysis of D0 → K−π+π+π− is performed. The asymmetries of D+ → KS/LK+(π0) and D0 → KS/Lπ0(π0) decays are measured. The branching fractions for D+ → 2KSK+, 2KSπ+, D0 → 2KS, 3KS as well as D0(+) → other 14 channels of PP final states are determined. Finally, the measurement of the Singly-Cabibbo-suppressed decays Λ+c → pπ+π−,pK+K−, the Cabibbo-favored decays of Λ+c → Σ−π+π+(π0) have been obtained.