We present our recent study \cite{scaling} on the scaling behaviour of the pions, kaons and protons $p_{T}$ spectra in proton-proton ($pp$) collisions with center of mass energies ($\sqrt{s}$ ) at 0.9, 2.76 and 7 TeV. This study shows that the scaling behaviour arises when a linear transformation, $p_{\rm T} \rightarrow p_{\rm T}/K$, is applied on these spectra. The scaling parameter $K$ depends on $\sqrt{s}$ and is determined the quality factor method. It also illustrates that the pions, kaons and protons originate from different distributions of clusters which are formed by strings overlapping, and the scaling behaviour of these identified particles $p_{\rm T}$ spectra could be understood with the colour string percolation model in a quantitative way simultaneously.