The emission spectrum of the B2Σ+→ X2Σ+ system of 12C18O+ has been investigated by using conventional spectroscopic techniques. The 0–1, 0–3, 1–2, 1–4 and 2–5 bands were recorded with high resolution (reciprocal linear dispersion was about 0.030–0.040 nm/mm) and spin splitting of the spectral lines has been precisely studied. Approximately 700 transition wavenumbers were measured with an estimated accuracy of 0.005 cm-1. The rotational analysis has been performed and molecular constants, for the ground X2Σ+ and excited B2Σ+ states, have been extracted. In particular, more reliable values of the spin-rotation interaction constants for the \(B^{2}\Sigma^{+}\ (v = 0, 1, 2)\) state were found to be: γ0=2.0415(37)×10-2 cm-1, γ1=1.9495(30)×10-2 cm-1 and γ2=1.8554(59)×10-2 cm-1, respectively. Also new values of the principal equilibrium parameters and vibrational terms values for B2Σ+ and X2Σ+ states have been provided.