The invention provides an advanced ash control rod and an absorber. The absorber is characterized in that the material contains terbium, terbium alloys or terbium compounds, wherein terbium elements account for 10-95% of the material of the absorber in percentage by mass. The ash control rod is of a long and thin solid tubular structure and is prepared from the material containing the terbium, the terbium alloys or the terbium compounds, wherein the terbium elements account for 10-95% of the material of the absorber in percentage by mass. According to the advanced ash control rod and the absorber, an ash control rod assembly prepared from the terbium, the terbium alloys or the terbium compounds is applied to a reactor, and the reactivity worth hardly changes along the burnup, so that the service life of the ash control rod assembly exceeds 20 years; neutron absorber materials (alloys or compounds of silver, hafnium, erbium, europium or dysprosium) with the reactivity worth decreasing along the burnup are utilized to counteract the reactivity worth, gradually increasing along the burnup, of the terbium, the terbium alloys or the terbium compounds.