On the Xingguang II laser facilities the soft X ray spectra of a laser –produced plasma of highly ionized 74W in the wavelength range 0.36 ~ 0.52nm were investigated with a plane crystal spectrograph. Four 3dj – nfj (n =5,6) resonance lines in Ni – like ions, as well as sixteen broad, characteristic, pseudo – continuous transition bands in Cu –, Zn –, Ga – and Ge –like ions, were measured and identified accurately. The wavelength precision is ± 0.0005nm. The relativistic Spin – Orbit – Split Arrays (SOSA) model, a particular case of Unresolved Transition Arrays (UTA), and the Xa method support this analysis: The succinct formulas of the mean wavelength vs the ionized stage were achieved first. The data of the experiment and the calculation have important uses for plasma diagnost