Whether an additional light scalar exists is an interesting topic beyond the Standard Model (SM), while nowadays we do not know exactly physics beyond the SM in the low mass region, e.g., the Atlas and CMS collaborations get inconsistent results at around 95 GeV in searching for light resonances in diphoton channel. Considering these, we study a light scalar in the Minimal Dilaton Model (MDM). Under the theoretical and latest experimental constraints, we sort the surviving samples into two scenarios according to the diphoton rate of the light scalar: the large-diphoton scenario (with sigma(gamma gamma)/SM greater than or similar to 0.2) and the small-diphoton scenario (with sigma(gamma gamma)/SM less than or similar to 0.2), which are favored by CMS and Atlas results respectively. We compare the two scenarios, check the characteristics in model parameters, scalar couplings, production and decay, and consider further distinguishing them at colliders. Finally, we get the following conclusions for the two scenarios: (i) The formal usually has small Higgs-dilaton mixing angle (vertical bar sin theta(S)vertical bar less than or similar to 0.2) and small dilaton vacuum expectation value (VEV) f (0.5 less than or similar to eta equivalent to v/f less than or similar to 1), and the later usually has large mixing (vertical bar sin theta(S)vertical bar greater than or similar to 0.4) or large VEV (eta equivalent to v/f less than or similar to 0.3). (ii) The former usually predicts small s gamma gamma coupling (vertical bar C-s gamma gamma/SM vertical bar less than or similar to 0.3) and large sgg coupling (0.6 less than or similar to vertical bar C-sgg/SM vertical bar less than or similar to 1.2), while the later usually predicts small sgg coupling (vertical bar C-sgg/SM vertical bar less than or similar to 0.5). (iii) The former can interpret the small diphoton excess by CMS at its central value, when m(s) similar or equal to 95 GeV, eta similar or equal to 0.6 and vertical bar sin theta(S)vertical bar similar or equal to 0. (iv) The former usually predicts a negative correlation between Higgs couplings vertical bar C-h gamma gamma/SM vertical bar and vertical bar C-hgg/SM vertical bar, while the later usually predicts the two couplings both smaller than 1, or vertical bar C-h gamma gamma/SM vertical bar less than or similar to 0.9 less than or similar to vertical bar C-hgg/SM vertical bar.
