Recently CERN has discovered three new exotic particles in LHCb. The particle are $T_{cso}$ $(2900)^{++}$, a doubly charged tetraquark with quark configuration (csu$\overline{d}$), $T_{cso}$ $(2900)^{0}$, a neutral tetraquark with quark configuration (cds$\overline{u}$) and a neutral pentaquark $P_{\psi s}$ $(4338)^{0}$ with quark configuration (c$\overline{c}$ uds) which is first observed pentaquark with a strange quark in its configuration. The discovery of these subatomic particles are exciting and the nature of interaction of the constituent quarks are need to be understood for these multiquark states. Diquark is one of the most important candidate for studying the structure and dynamics of exotic states. In the current work we have studied the properties of these particles in the frame work of diquark correlation. Diquark is a hypothetical coloured antisymmetric correlation of two quarks with spin 0 (scalar) or a vector with spin 1. We have suggested two models for diquarks. The composite fermion model and effective mass approximation model for diquark have been used to estimate the masses of $T_{cso}$ $(2900)^{++}$, $T_{cso}$ $(2900)^{0}$ and $P_{\psi s}$ $(4338)^{0}$. Results are found to be in good agreement with the experimental masses observed by CERN. We have also studied the higher states masses of the particles in the framework of the flux tube model which may be discovered in future. The regge trajectories are plotted. The form factor of these three exotics are also studied and plotted with different values of momentum transfer $Q^{2}$.