This invention relates to the field of chemical technology, specifically to a method for obtaining complex mineral fertilisers from phosphate ore, which includes the following stages: a) provision of sulphuric acid and potassium chloride; b) obtaining hydrochloric acid from potassium chloride and sulphuric acid, with the extraction of potassium sulphate, as a by-product; c) breaking down of phosphate ore using hydrochloric acid to obtain solid phosphates; d) processing of the solid phosphates from stage c) and potassium sulphate from stage b), if necessary, together with other sources of mineral components, into mineral fertilisers, as well as to the installation for implementing said method. The method indicated makes it possible to obtain complex mineral fertilisers such as PK and NPK-type fertilisers, which contain sulphur in an available form, using low cost raw components, furthermore it makes it possible to eliminate unnecessary transportation and logistical costs by virtue of combining the processes for obtaining the necessary fertiliser components in one place.