The 3D thermoluminescent spectra and glow curves of LiF:Mg,Cu,Si with various Mg, Cu and Si concentrations were measured. The shapes of the glow curves in LiF:Mg,Cu,Si, LiF:Mg,Cu and LiF:Mg,Si are similar and the glow curves have peaks at approximately the same temperatures, but with significantly different intensities. Neither the temperature of the glow peak nor the wavelength of the emission maximum changes with variation of dopants concentrations when Cu is more than 0.01 mol % in LiF:Mg,Cu,Si. The spectrum structure in LiF:Mg,Cu,Si, LiF:Mg,Cu and LiF:Mg,Si is similar in the 300-550 nm range. Some weak emissions around 610 nm are shown in LiF:Mg,Cu,Si with a Cu concentration of 0.01 mol % and in LiF:Mg,Si. It is concluded that Mg dopant mainly plays a role in the formation of trapping centres, both Cu and Si play a role in the main emission process and Cu also plays a role in reducing the emission around 610 nm.