The　difficulty　in　solving　distributed　order　differential　equations　lies　in　the　fact　that　the　order　of　the　derivative　is　distributed　within　a　finite　interval.　This　paper　discusses　the　initial　boundary　value　problem　of　three-dimensional　diffusion　equations　of　time　Caputo　type　distribution　order　and　the　initial　boundary　value　problem　of　three-dimensional　diffusion　equations　of　time　Caputo　type　space　Riesz　type　distribution　order.　The　analytical　solution　of　the　initial　boundary　value　problem　of　three-dimensional　diffusion　equations　of　time　Caputo　type　distribution　order　is　obtained　using　the　separation　of　variables　method,　and　the　analytical　solution　of　the　initial　boundary　value　problem　of　three-dimensional　diffusion　equations　of　time　Caputo　type　space　Riesz　type　distribution　order　is　obtained　using　spectral　method　and　Laplace　transform.　©　2024,　International　Association　of　Engineers.　All　rights　reserved.